Classifications

• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
  • C04B35/42—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on chromites
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
  • C04B35/03—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on magnesium oxide, calcium oxide or oxide mixtures derived from dolomite
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
  • C04B35/12—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on chromium oxide
• • C—CHEMISTRY; METALLURGY
  • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
  • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
  • C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
  • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
  • C04B35/44—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on aluminates

Definitions

• This invention relates to a refractory composition, for instance, such as is suitable for patching or maintaining a furnace lining, such as a furnace wall or roof; and more particularly it relates to a nonacid gunning composition for such use in high temperature metallurgical furnaces.
• a refractory mix such as nonacid or basic mix, made up of nonacid or basic grain material and a bonding agent
• patching material either by ramming into place or by placement by means of a nozzle-mix gun such as a Ridley gun (made by Ridley and Co.) or a Jet-Crete gun (made by Engineered Equipment, Inc.) or by a slurry gun, in which event the refractory composition is first formed into a slurry with water and is then gunned from a tank in the manner well known in this art.
• the refractory composition of this invention guns well onto a furnace wall, particularly when the latter is in heated state, and bonds well thereto; and that peeling away of the patch material upon further heating is substantially avoided.
• the composition adheres well to the hot surface and remains in good condition for a substantially longer time than other known gunning or ramming compositions for a similar use.
• the refractory composition herein consists essentially of a nonacid aggregate, preferably chosen from the group consisting of chromite, magnesia and mixtures of chromite and magnesia, and the bonding agent or agents shown below.
• One suitable composition consists essentially of from 50% to 95% of chrome ore, or chromite, from 0% to 45% of finely divided nonplastic magnesia, from 1% to of at least one bonding agent chosen from the group consisting of an alkali metal tripolyphosphate and tetra-alkali metal-pyrophosphate, from 0.05% to 3% of a plasticizing agent, and from 0% to 3%, preferably 0.5% to 3%, of finely divided iron oxide, as added.
• One preferred composition consists essentially of from 50% to 95% chromite, from 5% to 45 finely divided nonplastic magnesia, from 1% to 5% of the aforesaid bonding agent, from 1% to 3% of plastic clay and from 0.5 to 3% of finely divided, added iron ox- 3,278,320 Patented Get. 11, race ide.
• the refractory aggregate suitably is an admixture of coarse fired dolomite retained on 35 mesh and a minor amount of nonplastic magnesia passing 35 mesh.
• the chromite component of the present invention is suitably any chrome, or chromite, ore.
• chrome or chromite, ore.
• Masinloc chromite ore there can be employed.
• a Transvaal chrome ore having a typical analysis of the following ranges: 30% to 45% CI'203, t0 Slog, to A1203, to 29% Fe O 0.1% to 3% CaO, and 5% to 20% MgO. Any other desired chrome ore can be employed.
• the chromite component is preferably substantially all finer than 20 mesh when used in a gunning mix and about 50% to 65% of the minus 20 mesh material will pass through a 100 mesh screen.
• the magnesia component of the chromite and magnesia mixtures is any dead burned magnesia material such as periclase, for example, high purity periclase, or dead burned magnesite, etc.; and it is preferred that such magnesia component contain at least about of magnesium oxide.
• magnesia or periclase is the sole nonacid aggregate it is preferably periclase containing at least MgO.
• the magnesia material is fired to such state that there will be substantially no shrinkage upon further firing in place; and therefore a dead burned, hard burned or fused magnesia product is suitable for the magnesia component of the chromite-containing mixtures.
• a minor amount i.e.
• magnesia less than 50% of magnesia, where present, is used in finely divided state, in order to accelerate formation of a ceramic or mineral bond upon firing in place; and such magnesia is preferably employed in sizes of substantially less than 100 mesh.
• high purity periclase is employed as sole aggregate it is preferred to admix from about 0.5 to 1.5%, suitably about 1%, of a hydration inhibitor such as sodium borate decahydrate.
• the plasticizing agent where used is in readily dispersible form, e.g., as soluble in the mixing water or in finely divided form, and if an insoluble solid, is preferably all minus 200 mesh.
• a suitably plastic clay or bentonite can be employed as such plasticizer.
• an organic plasticizing agent such as sodium carboxymethyl cellulose, a watersoluble polymer of the sodium salt of acrylic acid (Cyanamer 370) and the like.
• from 0.05% to 3 of plasticizing agent is preferably employed. Where such plasticizer is a clay, it should be added in an amount of from 1% to 3%; and where it is an organic plasticizer, preferably from 0.05% to not over 1% is added. Mixtures of the plasticizing agents with each other can be employed, if desired.
• the iron oxide which is added is in very finely divided form and it has been found that an excellent source of iron oxide for this composition is the material which is deposited from the fumes issuing from oxygen steel converters in which a bath of molten metal is blown with oxygen to form steel. Large quantities of fumes issue from such converters during the blow and a major component of such fumes is finely divided iron oxide, substantially 90% passing through a 325 mesh screen. It is preferred that the iron oxide component be substantially entirely passing through a 100 mesh screen, but it is pre ferred for best results that at least 80% pass through a 325 mesh screen.
• any of the so-called precipitator dusts from steel plants, which are high in iron oxide, are suitable for use as the iron oxide component, that is, where they contain at least 85% of iron oxide.
• Another suitable iron oxide material is a very finely ground mill scale, and of the particle sizes noted as preferable herein.
• iron oxide can alternatively be provided by free iron oxide in the chromite ore employed; and in such event, added iron oxide may not be required, or a lesser amount may be required to provide total iron oxide within the range stated.
• the alkali metal tripolyphosphate which is employed as a bonding agent in the present composition has the following typical chemical composition: M P O where M is an alkali metal, such as sodium, potassium or lithium.
• M is an alkali metal, such as sodium, potassium or lithium.
• a preferred material is sodium tripolyphosphate Na P O also known as pentasodiumtriphosphate.
• a tetra-alkali metalpyrophosphate such as tetrasodium pyrophosphate, Na P O -10H O, which contains a minimum of 63.5% P in combination with Na O, or tetrapotassium pyrophosphate.
• the aggregate e.g., the chromite, magnesia, etc., the tripolyphosphate or tetrasodium py-rophosphate, or like salt, plasticizing agent and iron oxide components are mixed together in any desired sequence of steps and can be shipped and stored for use as desired. It is preferred that the material be kept out of contact with water until time for use because it readily sets up or bonds together in the cold upon the addition of water.
• the composition readily bonds to either hot or cold furnace wall surfaces; and that, as a gunning mix, it can be readily applied by means of the usual gunning devices, preferably a slurry gun, for such application of refractory materials. It is a particular advantage of the present invention that the composition is resistant to spalling, peeling and cracking under furnace operating conditions.
• gunning devices preferably a slurry gun
• EXAMPLE 1 A composition useful as a gunning mix is prepared as follows: There are admixed Masinloc chrome ore of the chemical composition and the particle sizing shown below, periclase as shown below, and the other ingredients, all in the amounts indicated:
• Precipitator dust from oxygen steel converter fumes (The precipitator dust contains 90% of particles passing through a 325 mesh screen and contains 90% of iron oxide.)
• the above ingredients are thoroughly intermixed and are shipped to the place of use where the mix is slurried in 2030% by weight of water and is applied to a hot furnace wall by means of a slurry gun of the type well known in this art. If desired, the slurry mix is placed in the gun device and the whole is then transported to the job. The mix is forced from the gun chamber by air pressure into the feed line where auxiliary air pressure forces it along and out through the nozzle, directed to the furnace wall.
• the gunning mix is applied to a hot open hearth furnace wall with the following results: A thin coating to V2 inch thick) is applied to the hot faces of existing refractory walls or roofs, and upon burning in forms a monolithic coating on the existing refractories, when? it absorbs fluxes which would otherwise attack the existing refractories and thus the mix protects the refractories and delays wear thereon.
• a very satisfactory gunning mix is obtained by admixing from 50% to chromite grains, from 5% to 45% finely divided nonplastic magnesia, from 3% to 3.5% sodium tripolyphosphate, from 1% to 3% bentonite and from 1% to 1.5% finely divided iron oxide, e.g. precipitator dust from oxygen converters as described above.v
• Example 1 1.0% of the finely divided iron oxide as shown in Example 1 and 3.2% sodium tripolyphosphate.
• the composition is applicable to a furnace wall by gunning in a manner as in Example 1.
• a further composition useful in this invention is prepared by admixing 94.3% of periclase of particle sizes about 17% by weight passing 20 mesh and retained on 65 mesh, 27% by weight passing 65 and retained on 200 mesh, 13% passing 200 and retained on 325 mesh and 37.3% passing 325 mesh, this periclase having a typical chemical analysis of 2.1% SiO 1.0% CaO, 0.4% Cr O 0.4% A1 0 0.6% R2 0 95.5% MgO (by difference); and 3.2% sodium tripolyphosphate, 1.5 bentonite and 1% sodium borate decahydrate.
• This composition is also applicable to a furnace wall by gunning as in the previous examples.
• the refractory composition of the present invention is suitable for use in high temperature furnaces, such as metallurgical furnaces, for instance open hearth furnaces and others.
• composition of the present invention instead of the sodium tripolyphosphate described above in the example, there can alternatively be employed a tripolyphosphate of potassium, lithium, ammonium or other alkali metal, ammonium being considered here as an alkali metal or equivalent thereof, except that the ammonium compound yields unpleasant fumes of decomposition upon mixing or burning in.
• the plasticizer Cyanamer 370 referred to hereinabove is made and distributed by American Cyanamid Company.
• Another suitable plasticizer is Carbopol 370R, made by B. F. Goodrich Chemical Company, which is a water-soluble resin.
• the mix contains, on the refractory oxide basis, from to 95% chromite and from 95% to 5% magnesia.
• Refractory composition consisting essentially of nonacid refractory particles chosen from the group consisting of magnesia, chromite, and mixtures of magnesia and chromite, from 1% to 5% of at least one bonding agent chosen from the group consisting of alkali metal tripolyphosphate and tetra-alkali metal-pyrophosphate, from 0% to 3% plasticizing agent, and from 0% to 3% added finely divided iron oxide.
• Refractory composition consisting essentially of from 50% to 95% chromite grains, from 0% to 45% finely divided nonplastic magnesia, from 1% to 5% of at least one bonding agent chosen from the group consisting of alkali metal tripolyphosphate and tetra-alkali metal-pyrophosphate, from 0.05% to 3% plasticizing agent, and from 0% to 3% added finely divided iron oxide.
• Refractory composition as in claim 2 wherein said bonding agent is sodium tripolyphosphate.
• Refractory composition as in claim 2 wherein said finely divided iron oxide is a dust recovered as a precipitate from the fumes issuing from an oxygen converter and contains at least 85% iron oxide.
• Refractory gunning mix consisting essentially of from 50% to 95% chromite grains passing a 20 mesh screen, from 0% to 45 finely divided nonplastic magnesia passing 100 mesh, from 1% to 5% of at least one bonding substance chosen from the group consisting of alkali metal tripolyphosphates and tetra-alkali metalpyrophosphates, from 0.05% to 3% of a plasticizing agent, and from 0.5 to 3% finely divided iron oxide.
• a refractory gunning mix consisting essentially of from 50% to 90% chromite, from 5% to 45 finely divided nonplastic magnesia, from 3% to 3.5% sodium tripolyphosphate, from 1% to 3% plastic clay, and from 1% to 1.5% finely divided iron oxide.
• Refractory gunning mix consisting essentially of about 82% chromite of particle size passing 20 mesh and 50% to 65% passing 100 mesh, 13% periclase of particle size passing 100 mesh, 3% to 3.5% sodium tripolyphosphate, 1% bentonite and from 1% to 1.5 iron oxide recovered from the fumes issuing from a zone wherein steel is produced by blowing molten ferrous metal with oxygen.
• Refractory composition consisting essentially of periclase particles, from 1% to 5% of at least one bonding agent chosen from the group consisting of alkali metal tripolyphosphate and tetra-alkali metal-pyrophosphate, from 0% to 3% plasticizing agent, and from 0% to 3% added finely divided iron oxide.
• a refractory admixture consisting essentially of from 5% to chromite, from 95% to 5% nonplastic magnesia, said chromite and said magnesia being expressed on the refractory oxide basis from 3% to 3.5 sodium tripolyphosphate, from 1% to 3% plastic clay and from 1% to 1.5% finely divided iron oxide, admixing therewith water in an amount of from 20% to 30% by weight of said admixture to form a slurry, and gunning said slurry onto a furnace wall.
• a refractory admixture consisting essentially of nonacid refractory particles chosen from the group consisting of high purity periclase, chromite, and mixtures of magnesia and chromite, from 1% to 5% of at least one bonding agent chosen from the group consisting of alkali metal tripolyphosphate and tetra-alkali metal-pyrophosphate, from 0.05% to 3% plasticizing agent and from 0% to 3% finely divided iron oxide, admixing water therewith in an amount of from 20% to 30% by weight of said admixture to form a slurry, and gunning said slurry onto a furnace wall.

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Cited By (10)

Citations (5)

• 1965
  • 1965-08-11 US US478980A patent/US3278320A/en not_active Expired - Lifetime
• 1966
  • 1966-08-05 GB GB35270/66A patent/GB1141623A/en not_active Expired
  • 1966-08-09 BE BE685286D patent/BE685286A/xx unknown
  • 1966-08-10 SE SE10849/66A patent/SE302098B/xx unknown

Patent Citations (5)

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